Don’t Destroy Me is the rather breathless title of Michael Hastings’s first play which he wrote when he was just 18. The material draws on his adolescent years in a south London boarding house and the action opens with an elderly husband, Leo, and his unfaithful young wife, Shani, preparing for a visit from their handsome teenage son, Sammy. Leo knows that his marriage is being undermined by Shani’s affair with a cocky spiv who lives next door but this tawdry business fades into the background as the play starts to come alive.

The characters upstairs take over. The flat above is occupied by Mrs Pond, a pretentious fraud in her early forties who is desperate for romance and attention. She earns money by reading tea leaves and she claims to have a husband, Jack, and a white rabbit living with her. Neither have ever been seen, possibly because they don’t exist.

Mrs Pond’s only real companion is her teenage daughter, Suki, who wears a party frock and always hopes to be invited to a ball. Both these needy women conduct their business on the landing of the boarding house where they engage passers-by in conversation. Suki, who describes herself as ‘a tight little virgin’, tries to attract young Sammy but she does so clumsily by berating him for his lack of experience and sophistication. Sammy is 15. Suki is 17. Their frenetic and confused snatches of amorous dialogue are the best thing in the play.

The costumes and the furnishings are as good as you’ll find in the West End. Designer Alex Marker has done a first-rate job of solving the awkward stage requirements. The script calls for a private apartment, a public stairwell and a twisted corridor with three front doors leading off it, and his solution is an amazingly subtle ensemble that fits snugly into the Arcola’s limited playing area. Visually this is world-class. Alas, the drama doesn’t quite match it.

The charming and funny first act gives way to a second half where the plot grinds to a halt and all the characters speak in the same petulant, self-pitying and aggressive tone. For the final 30 minutes, everyone on stage yells abuse at each other while indulging in minor acts of vandalism. Never a good way to end a play.

Protest Song is a 2013 drama by Tim Price whose biographical play about Aneurin Bevan opens next month at the National Theatre. The protagonist, Danny, is an angry tramp who gets swept up in the Occupy movement that established bivouacs in Bristol and elsewhere to express outrage at the capitalist system. Danny is an intensely difficult person to like because of his ungovernable temper and his habit of howling and swearing at complete strangers. Sadly, he blames his self-inflicted ruin on other people. His wretched state is reinforced by the system that exists to raise him out of poverty.

Homelessness charities encourage him to live in dirt-cheap hostels where he shares war stories and begging tips with other vagrants. Inevitably they develop a perverse pride in their destitution and they see their survival skills as proof of manliness and virtue. This is deeply depressing but easy to fix. If Danny were shipped out to a friendly village, where beggars are seldom seen, he’d be offered food and lodging in return for work. Within a day he’d learn how to look after himself.

1979 by Canadian playwright Michael Healey looks at the inglorious career of Joe Clark, who briefly served as Canada’s prime minister. He seemed to have lucked into power by default and after nine months in office he was ousted by Pierre Trudeau whom he had succeeded in the first place. On stage, Joe describes himself as a ‘Progressive Conservative nobody’ and the programme notes confirm that his character is ‘bumbling and unsure’. The play feels like a memo from the author to himself about the perils of picking the wrong subject for a drama. Poor old Joe lurks in his office like an anxious squirrel receiving visits from activists who are sharper and more articulate than he is and who bully him endlessly. One of his visitors, a young Stephen Harper, delivers a lengthy speech outlining a complete framework for government. And in 2006, Harper duly became prime minister and carried out the programme which, according to this play, he foresaw back in 1979.

This is a strange way to teach history. Newcomers to the subject are fed key information from an overhead screen rather than by an on-stage narrator. This method works well on film and TV, where viewers are accustomed to reading as they watch, but it seems a cumbersome device for live theatre. If you want a light-hearted and informative introduction to Canadian politics between 1979 and 2015, this is well worth seeing.